This invention relates generally to fans, and more particularly, to electric motor assemblies that include fans.
Fans are incorporated into different types of machines and systems including heating, ventilating, and air-conditioning (HVAC) systems. HVAC systems typically utilize supply and exhaust or return air fans. In addition, high-efficiency centrifugal fans have sometimes been used to supply air through duct systems and to cool motors. Such fans are chosen based on aerodynamic, economic, and functional suitability considerations.
Many HVAC systems utilize relatively large axial flow fans in condenser units to draw air across a plurality of condenser coils. These systems also typically utilize auxiliary centrifugal fans to draw cooling air through the axial fan motor. Such dual fan systems use a long shaft to mount the two separate fans. In addition, such systems, wherein an end user or wholesaler mounts the fans to a shaft, are subject to vibration and noise problems and require additional assembly.
In an exemplary embodiment, a motor assembly includes a compound fan assembly that generates axial air flow and centrifugal air flow. The fan assembly includes a body including an outer surface, a cavity defined by the body outer surface, a plurality of first blades disposed within the cavity, and a plurality of second blades that extend radially outwardly from the body outer surface. The fan assembly further includes a shaft concentric with the body, the second blades and a least a portion of the first blades configured to be rotatably coupled to the shaft. The first blades and the second blades are configured such that the first blades discharge air in a first direction and the second blades discharge air in a second direction.
In practice, the first blades draw air across a condensing unit, and the second blades draw air up through a motor to cool the motor. The motor shaft, the first blades, and the second blades are combined into a single part to improve efficiency. This single part is either manufactured through a molding process or assembled from components manufactured from stamped metal.